Depends on the type of trip.
If DH is with us, we tend to put more emphasis on finer dining & budget usually comes out to about $200 per day for the 3 of us (DH, Myself & 16 yo DS) 2 TS & 1 CS meal per day
Budget trip for DS & I this Aug, I am planning about $100 per day for the 2 of us, breakfast in the room, & mostly counter service - the extra $$ from the CS days will be well spent with a couple splurge meals at CG & Wolfgang Puck's.
When DS was younger & less of an eater, we could do budget trips for $50 a day for food - Now he eats more than that at one sit-down meal.